Seasonal Changes in Trans-Aconitate and Mineral Composition of Crested Wheatgrass in Relation to Grass Tetany

Abstract

Grass tetany (hypomagnesemia) frequently occurs from March through June in cattle grazing crested wheatgrass in western United States. High levels of transaconitate and/or citrate, K, K/(Ca + Mg) ratios and low Mg in the grass are implicated in the etiology of the disease. In the moist 1967 season, during periods of "flush" growth following warming trends, trans-aconitate and K increased while Ca and Mg decreased in crested wheatgrass. These characteristics may explain the incidence of grass tetany during periods of "flush" growth. During the dry 1968 season, these trends were not observed. Growth chamber studies confirmed some of the reasons for changes in crested wheatgrass composition observed in 1967 and 1968.